A PDP displays images by exciting a phosphor substance with ultraviolet light generated by gas discharge for light emission.
A PDP is roughly classified into the AC type and DC type by driving method, and the surface-discharge type and opposed-discharge type by discharging method.
In terms of moving to finer-resolution, an increase in the screen size, and easiness in manufacturing owing to simplicity of the structure, a PDP nowadays prevails with a three-electrode structure and the surface-discharge type.
A PDP is composed of a front panel and a back panel. The front panel has display electrodes including scanning electrodes and sustain electrodes; a dielectric layer covering the display electrodes; and a protective layer further covering the dielectric layer, on a substrate made of glass or the like. The back panel has a plurality of address electrodes orthogonal to the display electrodes, a dielectric layer covering the address electrodes, and partition walls on the dielectric layer. Arranging the front panel and the back panel facing each other forms a discharge cell at the intercept of the display electrode and the data electrode, where the discharge cell has a phosphor layer therein.
Such a PDP offers high-speed display as compared with a liquid crystal panel. In addition, it features a wide viewing angle, easy upsizing, and a high-quality display owing to its self-luminous property, attracting attention among flat-panel displays. It is widely used in various applications, particularly for a display apparatus in a public place where many people gather, and for enjoying a large-screen image at home.
In a PDP, at least one of a display electrode and address electrode requires a relatively high accuracy in its shape and allocation pitch. Therefore, so-called photolithography is used, where the whole surface of the substrate is coated with a conducting material such as a metallic material, containing a photosensitive material, which is exposed and developed using a photomask with an electrode pattern. A method for forming an electrode with a predetermined shape at a predetermined position of a substrate using photolithography is introduced in, for example, the 2001 FPD Technology Outlook (Electronic Journal, Co., Oct. 25, 2000, pp. 589-594, pp. 601-603, and pp. 604-607).
However, in the above-mentioned photolithography, if undesired dust or the like adheres to the exposure part of the photomask used, the photosensitive material corresponding to the part is not exposed to light and is not polymerized. Consequently, the material is dissoluted when developing, preventing a desired pattern to be achieved. In other words, a so-called “dropout” occurs in the pattern, causing a break in a part of an electrode.
A break in an electrode prevents supplying power to pixels on the downstream of the feed direction depending on a broken position. Such inconvenience and defects are fatal because they cause troubles in image display of a PDP.
The above describes an example for an electrode. In a PDP, despite its large screen, a structure other than an electrode requires accuracy. Consequently, photolithography is used also to form a structure, such as a partition wall, other than an electrode. Such a case also causes the same problems in image display as in an electrode.
Still, in the present invention, a structure of a PDP refers to that formed with photolithography, such as an electrode (e.g. address electrode and display electrode 6), a light-impervious layer, and partition wall 14.